Simple method for determination of triazolam in human plasma by high-performance liquid chromatography/tandem mass spectrometry

Triazolam was analyzed from human plasma samples by high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) with an MSpak GF polymer column (50 mm × 4.6 mm i.d., particle size 6 μm), which enabled direct injection of crude biological samples. Separation of triazolam, and lorazepam as the internal standard (IS) was carried out using 10 mM ammonium acetate (pH 3.56)–0.1% formic acid and an acetonitrile gradient elution. Both compounds formed base peaks due to [M + H]+ ions by HPLC/ESI-MS, and product ions were produced from each [M + H]+ ion as seen by HPLC–MS/MS. Quantification of triazolam and the IS in plasma samples was made by selective reaction monitoring using each base peak of product ions of HPLC–MS/MS. The recovery range of triazolam spiked into plasma was 86.4–92.7%. The regression equation for triazolam showed excellent linearity in the range of 0.25–20 ng/mL, and the detection limit was 0.1 ng/mL. Intra- and inter-day precisions for triazolam in plasma samples were not greater than 12.4%. Accuracy for the drug was in the range of 88.0–101.4%. Data obtained after oral administration of triazolam in male and female subjects are also presented.